Hemstitching device.



PATENTED MAY 9, 1905.

M. A. KRAG.

HEMSTITOHING DEVICE. APPLICATION FILED'IEBA, 1904.

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No. 7s9,220.

UNITED STATES Patented May 9, 1905.

MARTHA A. KRAG, OF BROOKLINE, MASSACHUSETTS.

HEIVISTITCHING DEVICE.

SPECIFICATION forming part of Letter; Patent No. 789,220, dated May 9, 1905.

Application filed February 4,1904. Serial No. 191,933.

To all 1071,0772 it may concern.-

Be it known that I, MARTHA A. KRAG, acitizen of the United States, anda resident of Brookline, in the county of Norfolk and State of Massachusetts, have invented new and useful Improvements in Hemstitchin g Devices, of which the following is a specification.

My invention is intended to provide an improved attachment for sewing machines whereby work having the appearance of being hemstitched may be produced, this result being accomplished by stitching together two layers of fabric with a slack stitch and then folding them in opposite directions along the line of stitching and separating them by a distance equal to the slackness of the stitches. The flaps thus folded back are then stitched down in lines parallel with the original line of stitching or otherwise, and the exposed slack stitches give the desired hemstitched effect. Various sewingmachine attachments have heretofore been devised for doing this kind of work in the manner above described; but, so far as I am aware, all these prior attachments have embodied a stationary separator having a thickness equal to the desired slack in the stitches and adapted to pass between the two pieces of fabric to be stitched together, which are passed one above and the other below the separator during the operation of stitching and are thus kept at the desireddistance apart. According to my invention, however, 1 produce the desired slackness in the stitches by causing a transversely-movable tooth or finger to pass with the fabric under the needle between its ascent and descent in forming a stitch in such manner that the needle-thread is carried over said tooth as the needle descends, the tooth being subsequently witl drawn from the stitch thus formed and leaving the latter slack to an extent determined by the size of said tooth.

My preferred form of attachment comprises a movable comb like structure the teeth of which are caused to pass successively beneath the needle, which comb-like structure is preferably located above the two layers of fabric instead of between the same and is so arranged that as the stitching operation proceeds each successive tooth of the comb intercepts the needle-thread and forms a loop in the stitch made simultaneously with the passing of such tooth beneath the point at which the needle reciprocates, the teeth being sub sequently withdrawn from the loops thus provided, as above stated. When the stitching has been completed, the two pieces of fabric are folded back along the line of stitching, stitched down, and separated as far as the slack stitches will permit, in the usual manner.

In the accompanying drawings, Figure 1 is a front elevation of an attachment embodying my invention in its preferred form, together with the adjacent parts of a sewing-machine. Fig. 2 is a side elevation of the same parts; and Fig. 3 is asectional plan view thereof, the plane of section being indicated by the line m m in Fig. 2. Figs. 4 and 5 are detail views, on an enlarged scale, showing more clearly the form of the loop-forming teeth hereinafter described. Figs. 6 and 7 illustrate the operation of the attachment and the appearance of the resulting work.

My preferred form of comb consists of a metallic disk having its periphery formed into or otherwise provided with a series of teeth extending in an approximate radial direction, continuous operation being thus provided and but little space being required for the location and operation of the attachment. Such a disk is shown at 2 in the drawings, said disk being provided with teeth 3 and arranged to turn freely on a central pivot 4, carried by an arm 5. The arm 5 is adapted to be detachably secured to some suitable part of the machine proper and preferably to the presserfoot or to some part moving therewith, as in this case the disk is moved into and out of contact with the fabric simultaneously with the usual movements of the presser-foot and is thus kept at all times in proper relation to the work. The mode of attachment of the arm 5 to the presser-foot will vary slightly, according to the specific construction of the machine with which my device is used, such attachment being provided for, according to the construction shown in the drawings, by means of a collar 6, notched to receive the vertical rod 7, which carries the presser-foot 8, and provided with a removable throat-block 9 and a thumb-screw 10, passing through the same, as shown in Fig. 3. The under side of the collar 6 is grooved to receive and fit the adjacent end of the presser-foot, so that said collar is prevented from turning on the rod 7, and the end 11 of the arm 5 is inserted into a perforation or recess formed in said collar, where it is held by means of aset-screw. The arrangement and adjustment of the parts is such that the teeth 3 at one edge of the disk are locateddirectly beneath the presser-foot and the pivot 4: is at one side of the needle with reference to the direction in which the fabric is fed, so that the teeth beneath the presser-foot at any instant may move forward with the fabric and the needle 12 may pass downward between any pair ofteeth brought beneath it, preferably about midway between the inner and outer ends thereof.

The teeth 3 are inclined backward somewhat with reference to the direction in which they move as the disk 2 rotates and are preferably given a shape best illustrated in Figs. 4 and 5, in which the tooth 3 is shown as having its top and bottom edges slightly beveled toward its outer end, its rear side being also beveled, as at 13, to give the tooth a relatively sharp top edge. The parts are so adjusted that the bottom edges of the teeth at the point where they come beneath the presser-foot are parallel with the feed-table 14, the object of this arrangement being to elevate the opposite edge of the disk slightly above the fabric, and thus prevent the feed-' ing of the fabric from being interfered with by its coming in contact with the disk or teeth at this point, and in order that this position of adjustment may always be established and maintained without difficulty I prefer to square the end 11 of the arm 5 and to give a corresponding form and the proper depth to the recess in the collar 6 which receives said arm, whereby said arm and disk are prevented from being misplaced in any way from the correct position of adjustment.

As thus constructed the operation of my device is as follows: The presser-foot 8 having been raised, the two layers or pieces of fabric to be stitched together are placed one directly upon the other and inserted beneath that edge of the disk 2 which lies beneath the presserfeet, which is then lowered, as usual, and thereupon the operation of stitching is performed in the usual way, the cloth being fed in the ordinary manner by the sewingmachine feed. The rate of feed is so adjusted that the number of stitches to the inch will be equal to the number of teeth 3 to the inch. Whenever the needle moves downward it passes between two of the teeth 3, and after it has moved upward the cloth is fed the length of a stitch and carries with it the adjacent teeth of the disk through an equal distance, so that when the needle next descends it steps,

as it were, over the tooth which has just passed beneath it, which tooth thus forms a stop for the needle-thread and draws it out to form a loop standing up from the upper surface of the fabric. In practice several disks will be provided for the same machine, said disks having differently spaced teeth to correspond with different rates of feed of the machine. So, too, for loops of different length d isks having teeth of correspondingly different thicknesses may be provided. After the first stitch has been taken the stitch last looped over one of the teeth carries that tooth with it as the fabric feeds, and the disk thus receives a stepby-step rotation, so that as the needle reciprocates it steps over the teeth 8 successively and leaves a loop over each tooth. Inasmuch as the top edges of the teeth are practically without width, it will be impossible for the point of the needle to catch on the top edge of a tooth and thus break the needle, and after the point of the needle has passed the top edge of any tooth it will hold the disk against rotati'on until the needle is again raised, thus insuring absolute uniformity in the stitching. The bevel 13 on each tooth also provides a cam-surface adapted to be engaged by the point of the descending needle. thus affording an independent means for insuring the step-by-step rotation of the disk. As the disk rotates the teeth which have been stepped over by the needle and carry the looped stitches gradually withdraw themselves from the loops as they move away from the line in which the fabric is fed, this result being facilitated by the backward inclination of the teeth and the downward bevel given to their top edges. The operation may therefore be continued without intermission as long as may be desired, so that an unbroken line of stitching of any desired length may readily be formed.

The operation above described is further illustrated in Figs. 6 and 7, in which 15 and 16 represent the two layers of fabric, and 17 represents the stitches. In Fig. 6 these stitches are shown as they are leftby the retreating teeth, only one tooth being illustrated in this figure. The layers of fabric may consist of two separate pieces, or they may be formed by folding a single piece of fabric over upon itself and cutting it along the line of the fold after stitching it. In either case the free edges of the fabric are subsequently folded in opposite directions along the line of stitching and stitched down, as at 18, the pieces of fabric being then separated as far as the slackness of the stitches will permit, leaving an open space between them, which is bridged by the stitches themselves, as shown in Fig. 7.

In order to prevent the advancing fabric from being caught by those teeth of the disk toward which the fabric is moving, I prefer to provide a guard covering a suflieient number of said teeth, which guard may consist of a thin metallic plate 19, attached to or forming a continuation of the arm 5 and having IIO its free end bent over the front edge of the disk and under the same, as shown in Figs. 2 and 3.

inasmuch as the teeth of the disk 2 inter vene between the presser-foot and the fabric, the pressure of the presser-foot on the fabric must be exerted, if at all, through said teeth, and it is therefore desirable that when the presser-foot is at the lower limit of its movement it should bear directly upon the upper sides of the adjacent teeth. As the presserfoot rises to permit the feeding of the cloth the disk rises with it, and since it is desirable that the disk when in this position should be free to rotate as the cloth feeds I prefer to provide for a slight movement of the disk away from the presser-foot as the latter rises, so that the two parts may then be out of contact with each other. This is readily accomplished by providing a slightly loose fit between the disk 2 and its central pivot 4, so that the disk may not only turn freely, but also tilt slightly on this pivot. The same result may be accomplished in various other waysas, for example, by prolonging the arm 5 and bending it over upon itself, as at 20, to permit a slight torsional spring action in that portion of said arm which carries the diskthe arrangement being such that the disk is normally held slightly out of contact with the under side of the presser-foot by such spring'action.

I regard it as an important feature of my invention that the stitch-intercepting part or member which secures the desired slackness in the stitches feeds with the fabric, as uniformity in the stitching is greatly promoted thereby. i also consider it to be one of the advantageous features of my invention that the two layers of fabric to be stitched may be placed directly in contact with each other and fed through the machine while thus in contact instead of being held apart by a separator, as a uniform feeding of the fabric is thereby secured, with the same accuracy as when two pieces of fabric are stitched together in the usual way. So far as I am aware, I am the first to provide an arrangement for the purpose described in the operation of which each slack stitch is produced by causing the needle to step over a transversely-movable tooth or finger as described, and hence I do not consider my invention to be limited to any one specific form or arrangement of this character nor to any particular manner of operating the same.

The construction herein described is my preferred construction, both because of its obvious simplicity and also because it does not require any special rotating or other feeding mechanism whatever, being operated with entire success by the ordinary operation of stitching, as above described.

I claim as my invention- 1. A hemstitching device for sewing-machines comprising a comb-like structure having an endless series of stitch-lengthening teeth adapted to extend transversely across the path of the needle, said teeth beinglaterally movable beneath the needle and with the fabric along the line of stitching.

2. A hemstitching device for sewing-machines comprising a comb-like structure having its teeth transversely movable with respect to the needle along the line of stitching; each of said teeth being tapered toward its outer end and provided with a sharp top edge.

3. A hemstitching device for sewing-machines comprising a comb-like structure having its teeth transversely movable with respect to the needle along the line of stitching, each of said teeth being tapered toward its outer end and provided with a sharp top edge, and also having its rear face beveled toward said top edge.

4; A hemstitching device for sewing-machines comprising a freely-rotatable disk provided on its periphery with outwardly-extending stitch-lengthening teeth, and means for attaching said disk with its teeth extending transversely across the path of the needle.

5. A hemstitching device for sewing-machines comprising a rotatable disk provided with peripheral teeth each tapered toward its outer end and inclined backward with respect to the direction in which the disk rotates, and attaching means for said disk.

6. A hemstitching device for sewing-machines comprising a rotatable disk provided on its periphery with outwardly-extending teeth havi-ng upwardly-beveled bottom edges and sharp top edges, and attaching means for said disk.

7. A hemstitching device for sewing-machines comprising a rotatable disk provided on its periphery with outwardly-extending teeth each taperedtoward its outer end and inclined backward with respect to the direction in which the disk rotates, said teeth having sharp top edges and also having their rear faces beveled toward said top edges, and attaching means for said disk.

8. A hemstitching device for sewing-machines comprising an arm adapted to be secured to the machine, and a freely-rotatable disk centrally pivoted to said arm and provided withperipheralstitch-lengtheningteethadapted to extend transversely across the path of the needle.

9. A hemstitching device for sewing-machines comprising an arm adapted to be secured to the machine, and a rotatable disk centrally pivoted to said arm and provided with peripheral teeth, said disk being capable of a tilting movement, for the purpose set forth.

10. A hemstitching device for sewing-machines comprising anarm adapted to be secured to the machine, a rotatable disk centrally pivoted to said arm and provided with peripheral teeth, and a guard covering a portion of the teeth of said disk.

11. A hemstitching device for sewing-machines comprising an arm adapted to be secured to the machine, and a rotatable disk centrally pivoted to said arm and provided with peripheral teeth inclined backward with respect to the direction in which the disk rotates, each of said teeth having outwardly-beveled top and bottom edges and also having its rear face beveled toward its top edge, substantially as described.

12. The combination withasewing-machine of a hemstitching device comprising stitchlengthening means extending transversely across the line of stitching and movable laterally with the fabric along said line of stitching when the needle is raised, said means being also movable away from said line of stitching.

13. The combination with asewingmachine of a hemstitching device comprising means located between the presser-foot and the fabric and movable with said presser-foot, and also movable with the fabric beneath the needle to intercept the thread upon the descent of the needle and forma loop therein, said intercepting means being subsequently removable from the loop thus formed.

14. The combination with a sewing-machine of a hemstitching devicecomprising a comblike structure having its teeth located between the presser-foot and the fabric and movable with said presser-foot and also along the line of stitching, said teeth extending transversely across said line of stitching.

15. The combination with asewing-machine of a hemstitching device comprising a rotatable disk having peripheral stitch-lengthening teeth, and means for securing said disk in predetermined relation to the machine, with a plurality of the teeth on one edge of said disk extending transversely across the line of stitching adjacent to the needle.

16. The combination with a sewing-machine of a hemstitching device comprising a rotatable disk having peripheral teeth, and means for securing said disk to the presser-foot of the machine, the teeth at one edge of said disk being located beneath said presser-foot and extending transversely across the iine of stitching.

17. The combination with asewing-machine of a hemstitching device comprising a rotatable disk having peripheral teeth, and means for securing said disk to the presser-foot of the machine, the teeth at one edge of said disk being located beneath said presser-foot and extending transversely across the line of stitching, and said disk being capable of a tilting movement with respect to said presser-i'oot.

18. The combination with asewing-machine of a hemstitching device comprising a rotatable disk having peripheral teeth beveled upwardly on their bottom edges, and means for securing said disk to the machine with the teeth at one edge of the disk extending transversely across the line of stitching adjacent to the needle, said disk being inclined atsuch an angle as will cause the bottom edges of the teeth adjacent to the needle to be parallel with the feed-table.

19. T he combination with a sewing-machine of a hemstitching device comprising a rotatable disk provided with peripheral teeth, and means for securing said disk to the presser foot of the machine, with the teeth at one edge of the disk located beneath the presserfoot and extending transversely across the line of stitching, said disk being capable of a tilting movement with respect to said presser foot and normally out of contact therewith when said presserfoot is elevated.

20. The combinationwith asewing-machine of a hemstitching device comprising a rotatable disk provided with peripheral teeth, each tapered toward its outer end and inclined backward with respect to the direction in which the disk rotates, and means for securing said disk to the presserfoot of the machine, with the teeth at one edge of the disk located beneath the presser-foot and extending transversely across the line of stitching, said disk being capable of a tilting movement with respect to said presser-foot and normally out of contact therewith when said presserfoot is elevated.

21. The combination with a sewing-machine of a hemstitching device comprising a rotatable disk provided with peripheral teeth, and

MARTHA A. KRAG. Witnesses:

E. D. CHADWIOK, HERBERT O. DAVIS. 

